Centrifugal engagement and disengagement drive systems

Abstract

A drive system may provide centrifugally driven clutch members into engagement and disengagement using weights between an interface of the clutch members. The weights maybe disposed in races between the clutch members. The weights may move centrifugally within the races pushing the clutch members apart during rotation of an input drive shaft. In some embodiments, two clutch members may provide the engagement and disengagement of the input drive shaft power to a drive output member and a third clutch member may be configured to engage the two clutch members during drive engagement. The third clutch member may be configured to disengage from the two clutch members as a failsafe during, for example, an overspeed condition or a jammed clutch interface.

We claim: 
     
       1. A drive system, comprising:
 a first clutch member coaxially adapted for connection to a shaft, the first clutch member including a first engagement face; 
 a second clutch member adapted for connection to a drive output member, the second clutch member including a second engagement face indexed for coupling to the first engagement face; and 
 a race defined by walls of the first and second clutch members, the race being disposed between the first and second engagement faces, the race extending radially toward circumferential edges of the first and second clutch members, the race configured to receive a weight that travels radially inwards towards or outwards away from the shaft, and within the race, and the first and second clutch members are adapted to engage with or separate from one another as the weight travels radially inwards towards or outwards away from the shaft in the race during rotation of the shaft. 
 
     
     
       2. The drive system of  claim 1 , further comprising a spring attached to at least one of the first and second clutch members, the spring configured to bias the first clutch member into engagement with or disengagement from the second clutch member. 
     
     
       3. The drive system of  claim 1 , wherein the race includes at least one tapering wall surface. 
     
     
       4. The drive system of  claim 3 , wherein the tapering wall surface tapers narrowingly toward the circumferential edges. 
     
     
       5. The drive system of  claim 1 , wherein the second clutch member is disengaged from the first clutch member in response to the weight moving radially outward toward the circumferential edges. 
     
     
       6. A drive system, comprising:
 a first clutch member coupled to a shaft; 
 a second clutch member operatively adjacent to the first clutch member, the second clutch member configured to:
 couple to the first clutch member in response to the rotational speed of the shaft equaling or falling below a first threshold rotational speed, and 
 de-couple from the first clutch member in response to the rotational speed of the shaft exceeding the first threshold rotational speed; and 
 
 a third clutch member configured to:
 couple to the second clutch member in response to the rotational speed of the shaft exceeding the first rotational speed. 
 
 
     
     
       7. The drive system of  claim 6 , further comprising a first weight adjacent the third clutch member. 
     
     
       8. The drive system of  claim 7 , wherein the first weight is configured to move centrifugally against the third clutch member. 
     
     
       9. The drive system of  claim 7 , wherein the first weight is disposed to move radially outward toward a circumferential edge of the third clutch member. 
     
     
       10. The drive system of  claim 8 , further comprising a second weight between the first and second clutch members disposed to move radially outward toward circumferential edges of the first and second clutch members during rotation of the shaft. 
     
     
       11. The drive system of  claim 10 , wherein a mass of the first weight does not equal a mass of the second weight. 
     
     
       12. The drive system of  claim 6 , further comprising a synchronization cone disposed between the second clutch member and the third clutch member configured to synchronize mating between the second clutch member and the third clutch member. 
     
     
       13. A drive system, comprising:
 a first clutch plate coupled to a shaft; 
 a second clutch plate including a first surface indexed to couple with a surface of the first clutch plate, the first clutch plate surface and the second clutch plate first surface including race wall surfaces configured to form a first race between the first and second clutch plates, the first race extending radially outward from the shaft toward circumferential edges of the first and second clutch plates; 
 a first weight disposed in the first race; 
 a third clutch plate coupled to a drive output member, the second clutch plate including a second clutch plate surface configured to:
 couple with a first surface of the third clutch plate in response to a radially outward movement of the first weight in the first race, and 
 de-couple from the first surface of the third clutch plate in response to a radially inward movement of the weight in the first race. 
 
 
     
     
       14. The drive system of  claim 13 , further comprising a fourth clutch plate including a surface configured to couple with a second surface of the third clutch plate, the fourth clutch plate configured to de-couple from the second surface of the third clutch plate in response to the rotational speed of the shaft exceeding a threshold. 
     
     
       15. The drive system of  claim 14 , further comprising:
 a second race disposed between the first surface of the third clutch plate and the surface of the fourth clutch plate race, the second race extending radially outward toward circumferential edges of the third and fourth clutch plates; and 
 a second weight disposed in the second race, wherein the fourth clutch plate is configured to de-couple from the third clutch plate in response to a radially outward movement of the second weight in the second race. 
 
     
     
       16. The drive system of  claim 15 , wherein a mass of the first weight is less than a mass of the second weight. 
     
     
       17. The drive system of  claim 14 , including:
 a first plurality of races between the first and second clutch plates; 
 a second plurality of races between the third and fourth clutch plates; 
 a first quantity of the first weights in the first plurality of races; and 
 a second quantity of the second weights in the second plurality of races, wherein the first quantity is unequal to the second quantity. 
 
     
     
       18. The drive system of  claim 17 , wherein the mass of the first weights does not equal the mass of the second weights.